Low‐Temperature Atomic Layer Deposited Electron Transport Layers for Co‐Evaporated Perovskite Solar Cells

In this work, we explore the potentials and the characteristics of electron‐transporting layers (ETL) grown by atomic layer deposition (ALD) at low temperature in co‐evaporated perovskite solar cells (PSCs). The thermal‐based ALD process has been investigated by tuning the main growing conditions as the number of cycles and the growth temperature. We show that un‐annealed ALD‐SnO 2 thin films grown at temperatures between 80 °C and 100 °C are efficient ETL in n.i.p co‐evaporated MAPbI 3 PSCs which can achieve power conversion efficiencies (PCEs) consistently above 18%. Moreover, the champion PSC achieved a PCE of 19.30% at 120 °C with 150 cycles. We show that the low‐temperature processed ALD SnO 2 is very promising for flexible, large‐area PSCs and mini‐modules. We also report the first co‐evaporated PSCs employing low temperature processed ALD ZnO with PCEs approaching 18%. This work demonstrates the potential of the low‐temperature ALD deposition method as a potential route to fabricate efficient PSCs at low temperatures.